• Journal of Korean Society of Forest Science
• /
• v.40 no.1
• /
• pp.63-69
• /
• 1978

A bark comprises about 10 to 20 percents of a typical log by volume, and is generally considered as an unwanted residue rather than a potential1y valuable resourses, As the world has been confronted with decreasing forest resources, natural resources pressure dictate that a bark should be a raw material instead of a waste. The utilization of the largely wasted bark of genus Pinus, Quercus, and Populus grown in Korea can be enhanced by learning their chemical properties. However, the chemical study of tree bark grown in korea have never been undertaken. In the present paper, the studies on the chemical properties of bark comprise carbohydrates, lignin, and extractives, composition of reducing sugars and five essential elements. The results may be summarized as follows: 1. Bark are much richer in quantity of lignin and extractives than the corresponding wood, and are chiefly consisted of lignin, extractives and carbohydrates orderly. It is the same with ash contents. Alcohol-benzene extractives of populus bark are the highest among three genus. 2. Although glucose constitutes the major sugar in both pine and hardwoods bark, in pinus, arabinose and xylose are the next but in hard woods, the next is xylose. 3. Essential elements, Ca and Kjeldahl-N are higher in the bark than in the wood. Ca content is the highest among others, and N,K followed it. Essential elements are higher in Quercus than in Populus and pinus.

• Journal of the Korean Wood Science and Technology
• /
• v.36 no.1
• /
• pp.88-101
• /
• 2008

The aim of this study was to attempt the efficacy of antifungal activity of the wood extracts against Botrytis grey mold. Wood chip derived from Quercus mongolica was obtain from steam explosion process and extracted by hot water and methanol and ethanol. The conidial germination was maximum growth with the application temperature for 20 and $25^{\circ}C$. In pH test, we observed the maximum growth in pH 5.0 and 7.0. Antifungal activity was the best in the hot water extractives against Botrytis cinerea. The separation of the antifungal substances was performed using a silica-gel column (n-hexane : chloroform : ethyl acetate : formic acid = 12 : 17 : 8 : 0.2, v/v/v/v), TLC and UV-Spectrophotometer, and isolated 6 fraction group. The result of antifungal activity in 6 fraction group, fraction group I and fraction group II were the highest antifungal activity against grey mold with the present study. Three peaks in fraction group I and II were detected by HPLC and this compounds were suppose to effective of antifungal activity.

• Journal of the Korean Wood Science and Technology
• /
• v.36 no.6
• /
• pp.33-40
• /
• 2008

Normally, cedar heartwood has a red color. However, it frequently changes black color (blackening phenomenon). It is reported that blackening phenomenon of cedar has been caused by oxidation of phenolics and norlignan extractives under weak alkaline conditions. In this study, heat treatment and UV irradiation were carried out to reduce the difference of color value between blackened wood and bright sap wood. Effects of temperature, moisture content, treatment time and light on decrease of color difference between blackened heartwood and sapwood were evaluated in each treatment. A decrement of different color value between blackened heartwood and bright sapwood by hot-water treatment was bigger than others. An effect of the vacuum drying was similar to that of the kiln drying. UV irradiation decreases the color difference between dried blackened heartwood and bright sapwood. It is suggested that UV irradiation could be used as final treatment to reduce the color difference on wood during drying process. Determination of optimum conditions and development of hybrid process for control of discoloration will be needed in a further study.

• Journal of the Korean Wood Science and Technology
• /
• v.33 no.1 s.129
• /
• pp.77-86
• /
• 2005

In order to investigate the ability of log wood for oak mushroom production as a source of an alternative energy, both chemical and physical characteristics of log wood were investigated according to the cultivation periods. Also, both chemical and physical characteristics of material that treated by steam explosion were investigated to confirm the pretreatment effect by remaining enzyme as a control. The contents of ash, water-, alkali- and organic soluble extracts have been increased after the inoculation. It appeard that holocellulose contents substantially decreased and the contents of lignin as another main component of wood remained constant after the inoculation. However this result implied that indeed, a sufficient amount of lignin has been degraded paritially by enzymes of oak mushroom Lentinus edodes if we consider that the amount of holocelulose was substantially reduced. It also indicated that the degree of degradation gradually progressed but crystallinity decreased after the inoculation. The contents of water-, alkali- and organic soluble extracts have been increased by steam explosion. Holocellulose contents increased within narrow limits and lignin contents remained constant. However the contents of holocellulose and lignin have been decreased by steam explosion, considering that the amount of other extractives was relatively increased. The degree of crystallinity and lignin contents reduction by steam explosion was almost similar to the result obtained by increasing cultivation periods. According to the results, log woods for mushroom production have a potential as material for developing alternative energy.

• Journal of the Korean Wood Science and Technology
• /
• v.30 no.1
• /
• pp.63-71
• /
• 2002

The bark of P. alba × glandulosa, P. euramericana and P. nigra × maximounczii F₁, several Populus trees, were collected, extracted with acetone-H₂O(7:3, v/v), fractionated with hexane, chloroform and ethylacetate, and freeze dried to give some dark brown powder. Each fraction of the powder was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluents and then identified by thin layer chromatography using TBA and 6% acetic acid as developing solvents. The structures of the isolated compounds were characterized by ¹H, ¹³C and 2D-NMR tools including mass spectrometry. Most of the compounds were flavonoids and salicin derivatives as follows: (+)-catechin, taxifolin, aromadendrin, eriodictyol, naringenin, sakuranetin, sakuranetin-5-O-𝛽-D-glucopyranoside, neosaturanin, salireposide, p-coumaric acid, and aesculin from P. alba × glandulosa, (+)-catechin, salireposide, populoside and salicortin from P. euramericana and (+)-catechin, quercetin, padmatin, salireposide, populoside and salicortin from P. nigra × maximounczii F₁.

• Journal of the Korean Wood Science and Technology
• /
• v.44 no.1
• /
• pp.135-146
• /
• 2016

Three fiber sources including Russian spruce (Picea jezoensis) and larix (Larix leptolepis), and Myanmar bamboo (Phyllostachys bambusoides) for thermomechanical pulp were explored to replace domestic pine (Pinus densiflora) pulp that has some limitations in an aspect of supply and pitch trouble. Thermomechanical pulps were manufactured under the identical condition, and then compared with their representative pulp properties and pulping process. Both Russian larix and Myanmar bamboo contained large amounts of extractives that would negatively affect mechanical pulping processes. Russian spruce showed the least contents in shives and pitch. Russian spruce and domestic pine reached an optimum freeness level within a short pulp processing time, which consumed less amount of refining energy compared to larix and bamboo. In particular, the spruce wood showed the highest brightness level which might lead to a less consumption of bleaching chemicals. It was expected that Russian spruce could be replaced with the domestic pine wood in respect of both pulping process and pulp quality.

• Journal of the Korean Wood Science and Technology
• /
• v.28 no.3
• /
• pp.25-33
• /
• 2000

This study was carried out to find the optimal isolation conditions of xylan from steam-exploded materials, such as rice straw(Oryza sativa), barley straw(Hordeum vulgare) and oak wood(Quercus mongolica), In the chemical composition, we found that the contents of water-extractives and ash of rice straw and barley straw were more than those of oak wood. Rice straw, barley straw and oak wood were steam-exploded at 20kgf/$cm^2$ for 3 minutes or 6 minutes. The content of lignin in three different steam-exploded materials was higher than that of non-treated materials. The crude xylan was extracted with hot water and 0.5% KOH solution from steam-exploded materials. In the sugar type of crude xylan extracted with hot water and 0.5% KOH solution, the oligomer content of crude xylan extracted with hot water was much more than that of crude xylan extracted with 0.5% KOH solution. The crude xylan was purified with 5% barium hydroxide Solution and ethanol precipitation procedure. The content of xylose of purified xylan was over 85%, but other sugar residues(arabinose, mannose, galactose and glucose) were not removed completely.

• Journal of Korean Society of Forest Science
• /
• v.96 no.4
• /
• pp.408-413
• /
• 2007

The dried bark of Platycarya strobilacea were ground, extracted with 95% EtOH, concentrated, and one of EtOH extracts was fractionated with a series of n-hexane, dichloromethane and another was fractionated with a series of petroleumether, $Et_2O$, ethyl acetate on a separatory funnel. A portion of dichloromethane soluble was chromatographed on a Sephadex LH-20 column ($72.0{\times}5.0cm$) using EtOH-$CHCl_3$ (7:3, v/v) as eluent and A portion of $Et_2O$ soluble was chromatographed on a silica gel column ($42.0{\times}3.5cm$) using $CHCl_3$-MeOH (9:3, v/v) as eluent. The isolated compounds were identified by TLC, $^1H$-, $^{13}C$-NMR, HMBC and EI-MS. Two flavonoids and three flavonoid glycosides were isolated from the bark of P strobilacea. The structures were determined to quercetin (compound 1), myricetin (compound 2) as flavonol compounds and afzelin (compound 3), quercitrin (compound 4), myricitrin (compound 5) as flavonol glycosides, respectively, on the basis of spectrosopic data.

• Journal of the Korean Wood Science and Technology
• /
• v.6 no.1
• /
• pp.3-7
• /
• 1978

Quercus serrata degraded by Leminus edodes(berk) Singer was investigated. In order to evaluate on affect of the fungi on the sound logs, and the logs attacted for 2 years and five years were used as a sample tree. Large portions of carbohydrate mainly was decomposed by the fungy. It is supported by the increasing of alkaline extractives and the breaking up of crystallinity. Lignin is transformed considerably as shown the results of the determination of Klason lignin, gel filtration and nitrobezene oxidation. On the other hand, the decreasing of methoxyl group and the increasing of carboxyl group in parallel with demethlation and acidification are presented. Syringyl nuclei unit is decomposed easier than guaiacyl unit. It is also illustrated that the more decreasing of carboxyl group compared with aldehyde group was acidified biodegradation.

• Journal of the Korean Wood Science and Technology
• /
• v.27 no.1
• /
• pp.105-114
• /
• 1999

Antimicrobial activities of the organosoluble extracts, seperated fractions and isolated lignans from the leaves tissue of Magnolia kobus DC. var. borealis Sarg. were investigated. The results are summarized as follows : 1. The inhibitory components against the spore growing test were concentrated on light petroleum ether and diethyl ether soluble fractions. The light petroleum ether solubles of the leaves tissue had terpenes compound, so, that they caused growing inhibition. These appearance showed high values of Rf on TLC bioautography and GC analyses with monoterpenes. 2. In the lignans, syringaresinol(X III), medioresinol(VI), phillygenin(VIII), kobusinol A(X) showed relatively high inhibitory effects in the spore growing test, and these are all showed structural characteristic of the phenolic hydroxyl group of guaiacyl and syringyl skelecton. 3. The light petroleum ether soluble fraction showed the strongest inhibitory effect against the antimicrobial activity in the seperated fractions. 4. The inhibitory effects of the lignans against the bacteria showed not so pronounced independantly, but the extracts and separated fractions contained with these lignans showed something synergism.